LADVD is a daemon to handle link-layer advertisements on UNIX.
It can send and receive frames for the LLDP, CDP, EDP, FDP and NDP
protocols. These are used to inform devices about the equipment
on the other side of an ethernet link. This includes hostname,
port information and more. For example, a switch can display a
list of which device is connected to each port.

LADVD uses privilege separation; privileges are required to handle
raw sockets and certain ioctl()s. Network data is parsed by an
unprivileged child process.

Every 30 seconds the child generates advertisement frames reflecting
the current system state. Interfaces (bridge, bonding, wireless),
capabilities (bridging, forwarding, wireless) and addresses (IPv4,
IPv6) are detected dynamically. Secondly ladvd can listen for incoming
frames and utilize these for various features (protocol auto-enable,
logging, interface descriptions).
